Aspects of the disclosure relate to location-based services for mobile wireless devices. In particular, various aspects of the disclosure relate to Secure User Plane Location (SUPL) technology.
Location services for mobile wireless devices enable the current location and, in some cases, speed and heading of a mobile wireless device to be obtained and provided to the wireless device (e.g., to an application running on the wireless device or to the user of the wireless device) or to some third party application. Examples of a third party application may include an emergency services provider (e.g., in the case of an emergency call from the wireless device) or some external provider of commercial services that depend on knowing the wireless device's current or previous location. For wireless devices that may access different types of wireless communication networks, location services may typically be supported using a location server that can be accessed from, and in some cases may be resident within, the wireless network currently being accessed by the wireless device.
The role of the location server may be to assist the wireless device to make appropriate location related measurements (e.g., measurements of radio signals from base stations in the serving wireless network or measurements of various global navigation satellites). Additionally, in some cases, the location server may compute the wireless device's location based on these measurements. The location server may also be used to relay a wireless device's location to entities authorized to receive the location and to convey the wireless device's location to the wireless device in the event that the location server rather than wireless device had computed the location.
Current user plane location services, such as the Secure User Plane Location (SUPL) service defined by Open Mobile Alliance (OMA), can include a target mobile device (e.g., SUPL Enabled Terminal (SET)) and a location server (e.g., a SUPL Location Platform (SLP)).
A home location server (e.g., a Home SLP (H-SLP) in the case of SUPL) is a location server permanently affiliated with a number of target mobile devices (e.g., based on service subscription). A home location server would sometimes belong to a home network operator of the target device, in the case of mobile wireless devices.
A location server without a pre-provisioned permanent affiliation with a set of target devices may be referred to as a discovered location server. In the case of SUPL, a discovered location server is referred to as a Discovered SLP (D-SLP). A discovered location server can be found by, or provided to, a target mobile device based on its current location, currently used access network(s) and/or the current date and time and could belong to or be associated with, a non-home network operator or some other non-operator provider of location services. A D-SLP is an SLP able to provide service to a SET in areas where the H-SLP is unable to provide service or unable to provide service at the requested quality of service (e.g., accuracy, time to fix). Additionally, an Emergency SLP (E-SLP) may support location services for an emergency call made by the SET user.
There may be a benefit (e.g. in terms of reduced delay and/or better quality of location service) to making a mobile terminal (e.g. a SET) aware ahead of time of one or more home location servers (e.g. H-SLPs) and/or discovered location servers (e.g. D-SLPs) that the mobile terminal may use to obtain location services at different locations and when using different access networks.